Hello all, I was thinking about using Xylotec to convert my jig borer to a mill and the xylotec guy told me that for my machine (due to size) I should probably use Gecko drives.
I have searched the Gecko website and gone through this forum and cannot seem to find a place that lists recomendations for drivers and motors based upon size of machine and use.
It's use will be mainly aluminum and steel milling.
I need a 3 axis setup that will have enough power and speed for "one offs" and prototype work. this is stictly a hobby for me. no production work.
That being said I would like to build a quality mill out of my quality jig borer.
Incase you need to know-
machine weight with base 800 lbs
table weight approximately 30-40 lbs
This has the Z on the collum. (not a knee mill)
Table approximately 8" x 14".
The leadscrews are 10tpi and ground. dials are graduated with verniers at .0001 approximate diameter of the leadscrews is 1".
I am not new to machining or running cnc's (I used to operate nasa retrofit cnc moore jig griinders) I am however in the dark as to how to determine the correct motors and drivers and power supply.
Cost is an issue. I am willing to sacrifice some speed for affordability, but I still need a useable machine.
nate your gonna have to dig and dig, and dig some more :-). there is a LOT of info here. I read and read and read and FINALLY after I ordered my 1150 oz/in step motor found some confirmation that it is in fact large enough for my bridgeport. :-).
Your machine to do it really nice I think you will want to convert it to ball screws, ans your job is easier than mine on a 9x42 bridgeport because your table travels are smaller, and you can thus use the much more common ballscrews.
Ebay is a good place to start looking, I have not bought any there but I have seen many the general size of your machine.
I am using as I said 1150 oz/in step motors from kelingnc, I bought his 72 volt 20 amp power supply,
http://www.kelinginc.net/index.html There are some innovations coming from Gecko that make it worth the extra $$ to get double shafted step motors for encoders I think. I shopped for motors on Ebay and got tired of looking at dusty junky crap that I figuired would just toast my gecko's :-) so I'm buying new ones. It is important to shop around because all the guys that sell thru the zone offer deals when you but step motor drivers and step motors together, or you buy Mach 3 and motors...hard to decide, it just boils down to who has exactly what you want.
I will use 1:2 reduction via toothed belts..2 turns on the motor to 1 of the leadscrew. If I were you I would design my motor mounts so that you can run several ratios's by just changing pulleys.
https://sdp-si.com/eStore/ These guys have the toothed belts and pulleys. I ended up choosing the GT2 5mm pitch with a 15mm wide belt for what I'm doing.
Just in general for your machine I think you would want .200" lead ballscrews...then you have to figuire out how to mount the ballnuts (easier in that dept to buy already made for my brodgeport)
if you are thinking about rolled thread ballscrews this gentleman here has a very good price on the 5/8 ones http://www.homeshopcnc.com/ and he referred me to mcmaster-carr for larger sizes, 5/8 might fly on your machine just fine.
Thanks you so much for replying. sometimes posts just get ignored. I have been reading, reading, reading...
I have determined that I will use (NEMA 34 HIGH TORQUE STEPPER MOTOR 1160 oz-in, ½” Shaft with a flat, 118mm) from keling.
I talked to Gecko today and the lady recomended the G202's for my application.
I had not yet determined which PS to use. Mabie the one you chose?
my machine is about half the size of your bridgeport. but I would rather have motors that were a bit oversized than undersized. especially since I intend to do steel milling regularly.
could you please explain why you are using reduction pulleys? Is it to get max power and torque out of your steppers so you can run really agressive cuts on steel??
I had not anticipated needing to run reduction pulleys on my machine. do you think its nessicary or is it just to give me the versitility to run fast with less torque and slow with more torque?
I like the looks of the 5/8 rolled ballscrews. fortunately I can finish the ends myself. assuming they are just case hardened. I do have an od grinder if they are through hardened, but it will not thread. only grind.
I don't think anybody really ignores threads, there is just so much material here in so many areas that nobody can see it all, people will subscribe to your thread and then it is easy to see when you post. It seems to subscribe you to any thread you post on too, you will find your subscribed threads in "user cp" if you didnt already :-).
I hear the 202 is a smoother drive than the 201, I have one 201 and one step motor right now, trying to decide whether to get the 203v's for the next two....they look really nice.
I chose the 1:2 ratio when I was first selecting the motors, and unsure if they were large enough. If you do the math the motors are 1.8 degree motors, that equals 2000 microsteps per revolution, which on my .200 lead ballscrews with 1:2 reduction gives me .00005" per microstep. I am going to run the acme leadscrews first so the 1:2 will I guess be about right for that added friction....I hope :-). You have picked the same motor's I did I think, as I said consider the dual shaft so you can add encoders....the GREX is supposed to be able to run steppers in closed loop if all goes according to plan and that will be the cats *ss when Mariss works it out.....and the guys with one shaft motors will just have to set on the sidelines and watch :-). Even if you run 1:1 I think the toothed belt and pulleys are a better way to isolate the motor than a coupling, and it opens you up to doing other than 1:1 by just changing pulleys.
The co. I sent the link for says they do work on the leadcrews, I would ask for a quote at least if you cannot thread :-). Or I'm sure there are other guys that would trade some lathe work for some OD grinder work :-).
For 3 axis I think the PS I bought is maybe a bit on the big side, BUT it leaves me more amps avail to run a 4th axis..milling is so much more fun with a 4th axis.
Stop over on Adobe's lathe conversion thread if you want to see some nice work, he is a friendly fella too :-). I have a thread up called "my bridgeport" not a lot done yet, we will get there :-).
Sometimes figuiring on all this stuff makes my head hurt, but it keeps me busy :-).....wiring diagrams, electrical formulas....NCCAMS lectures on ABEC 7 AC bearings...all that fun stuff.
I have heard Linleys are excellent machines :-).........
I am not sure english is your first language so if some of my blabber is hard to follow, just yell and I will slowwwwww down hehe
LinkBack URL
About LinkBacks
Converting Linley Jig borer to CNC Mill. 
